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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<style>
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: 200px;
  background-color: #f1f1f1;
}

li a {
  display: block;
  color: #000;
  padding: 8px 16px;
  text-decoration: none;
}

li a.active {
  background-color: #4CAF50;
  color: white;
}

li a:hover:not(.active) {
  background-color: #555;
  color: white;
}
</style>
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<h1>垂直导航栏</h1>
<p>在此例中，我们创建一个具有绿色背景色和白色文本的 "active" 类。该类将添加到 "Home" 链接。</p>

<ul>
  <li><a class="active" href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li><a href="#contact">Contact</a></li>
  <li><a href="#about">About</a></li>
</ul>


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